Closed circuit blade-cooled turbine

ABSTRACT

In a closed circuit moving blade cooled turbine, holes in the radial direction formed in the outer periphery of a second stage wheel are led to cooling air supply holes to second stage moving blades and to prevent the cooling air from leaking into the junction, the holes in the radial direction and the cooling air supply holes are interconnected and the supply members covering the junction are fit into them. The cooling air after cooling the second stage moving blades is introduced into the collection holes formed in the outer periphery of the spacer via the cooling air collection holes and to prevent the cooling air from leaking into the boundary, the cooling air collection holes and collection holes are interconnected and the collection members covering the boundary are fit into them. To make the sum of minimum sectional areas of the respective paths of the second stage moving blades smaller than the sum of minimum sectional areas of the respective paths of the first stage moving blades, a minimum sectional member is incorporated into the supply member.

BACKGROUND OF THE INVENTION

The present invention relates to a closed circuit blade cooled turbinefor improving the performance of gas turbine equipment by supplying arefrigerant inside the moving blades of a turbine, circulating andcollecting it.

A conventional turbine moving blade cooling system is generally a closedcircuit blade cooling system for warming or cooling a wheel which is aholding member of the moving blades first by introducing air extractedfrom an optional stage of a multistage compressor to a rotor which is amultistage turbine group, moderates the temperature gradient generatedin the wheel, and then cooling and lowering the moving blade metaltemperature by supplying and circulating air inside the moving blades,and discharging air after cooling into the gas flow path of the turbineas it is.

However, recently in gas turbine equipment, for the purpose of energyconservation and environmental maintenance, realization of highefficiency of a system has been required. As a means of realization ofhigh efficiency, a closed circuit blade cooling system is used, whichsystem has a constitution that a cooling medium (hereinafter referred toas a refrigerant) after cooling of the moving blades is all collectedwithout discharging it into the turbine gas flow path as exhaust gas asit is and returned between the compressor and the combustor via thereturn line.

Thereby, not only the loss extracted from the compressor as arefrigerant is recirculated and made up but also the thermal energyreceived by turbine cooling is added to gas before combustion and hencea constitution that high efficiency improvement is available isrealized.

Such a closed circuit blade cooling system or turbine is described in,for example, Japanese Patent Application Laid-Open 7-189740 and JapanesePatent Application Laid-Open 9-242563.

Meanwhile, in the closed circuit blade cooling turbine, a refrigerant tobe supplied from the still side is generally supplied to the rotor via asingle supply path without distinction of a refrigerant for the firststage moving blades (moving blades positioned on the uppermost streamside of main gas of the gas turbine) and a refrigerant for the secondstage moving blades (moving blades positioned on the downstream side ofthe first stage moving blades) and also when the refrigerant is to becollected on the still side from the rotor after cooling each movingblade, it is collected via a single collection path without distinctionof the refrigerant for the first stage moving blades and the refrigerantfor the second stage moving blades. Therefore, the branch point of arefrigerant to be supplied to the first stage moving blades and thesecond stage moving blades and the junction of a refrigerant to becollected from the first stage moving blades and the second stage movingblades are located inside the rotor. Between the branch point and thejunction in the rotor, a refrigerant supply flow path and a refrigerantcollection flow path for the first stage moving blades and a refrigerantsupply flow path and a refrigerant collection flow path for the secondstage moving blades are installed and these flow paths have a pluralityof parallel flow paths for refrigerant supply and a plurality ofparallel flow paths for refrigerant collection which are connected tothe respective refrigerant paths in the moving blades at each stage.

However, there are the following problems imposed in a conventionalclosed circuit blade cooling turbine.

Since main gas passing through the second stage moving blades does itswork in the first stage moving blades, the temperature of main gas inthe second stage moving blades is lower than that of the first stagemoving blades. When the temperature of main gas at the outlet of thecombustor is on the level of 1500° C., the difference in the temperatureof main gas between the first stage moving blades and the second stagemoving blades is more than 200° C. Even if the allowable metaltemperature of the first stage moving blades is made higher than that ofthe second stage moving blades depending on the material characteristicssuch as the material kind, single crystal, polycrystal, and others, itis impossible to compensate for more than 200° C. of difference in thetemperature of main gas by the material and hence it is necessary thatthe first stage moving blades supply and cool a refrigerant at a flowrate higher than that of the second stage moving blades.

Inside the rotor, as mentioned above, the refrigerant flow path(refrigerant supply flow path and refrigerant collection flow path) forthe first stage moving blades and the refrigerant flow path (refrigerantsupply flow path and refrigerant collection flow path) for the secondstage moving blades are installed. In this case, assuming that the flowresistance of the refrigerant flow path for the first stage movingblades and the flow resistance of the refrigerant flow path for thesecond stage moving blades in the moving blades and rotor are equal toeach other, a refrigerant in the same amount flows through the firststage moving blades and second stage moving blades respectively.

However, by doing this, as mentioned above, an appropriate refrigerantflow rate cannot be distributed in the first stage moving blades andsecond stage moving blades which are different in the necessaryrefrigerant flow rate. Namely, if a necessary amount of refrigerant issupplied to the first stage moving blades, an excessive amount ofrefrigerant flows through the second stage moving blades and the thermaleffect of the turbine is reduced. Inversely, if a necessary amount ofrefrigerant is supplied to the second stage moving blades, therefrigerant of the first stage moving blades is insufficient and thefirst stage moving blades exceed the allowable metal temperature.

On the basis of the aforementioned respects, even if the sectional areaand resistance of the refrigerant supply flow path in each of the rotorand moving blades are estimated at the design stage and each refrigerantflow path is designed and manufactured on the basis of it so that anappropriate flow rate flows in the moving blades at each stage, actuallyvariations are easily caused to each product and after assembly andmanufacture, when the metal temperature of each of the first stagemoving blades and second stage moving blades is deviated from the designvalue, it is necessary to adjust the flow rate distribution of arefrigerant to be supplied depending on the metal temperature of each ofthe first stage moving blades and second stage moving blades.

A refrigerant supplied to the rotor via the single supply path isbranched to a refrigerant for the first stage moving blades and arefrigerant for the second stage moving blades in the rotor and therefrigerants after cooling the first stage moving blades and secondstage moving blades join in the rotor and are collected outside therotor via the single collection path. Therefore, it is necessary toadjust the refrigerant flow rate of each of the first stage movingblades and second stage moving blades and in this case, it is necessaryto consider at what position of the refrigerant flow path the flow pathresistance for flow rate adjustment is to be set.

In the general constitution of the rotor that the rotor is locked withbolts with a plurality of wheels and spacers overlapped in the axialdirection, when a flow path resistor is installed inside the rotor,whenever the flow rate for the moving blades at each stage is to beadjusted, it is necessary to remove the locking bolts of the rotor andbreak down it and hence the operation is complicated extremely and theoperation time and cost are increased. Therefore, it is a problem how toadjust the flow rate simply without breaking down the rotor.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a closed circuit bladecooled turbine in which a refrigerant can be supplied to and collectedfrom each of first stage moving blades and second stage moving bladeshaving a necessary high refrigerant flow rate at an appropriate flowrate distribution.

Another object of the present invention is to provide a closed circuitblade cooling turbine in which a refrigerant flow rate to the movingblades at each stage can be simply adjusted without disassembling therotor.

(1) To accomplish the above first object, the present invention providesa closed circuit blade cooling turbine having moving blades at aplurality of stages arranged in the flowing direction of main gas of agas turbine and fixed to the outer periphery of a rotor, supplying arefrigerant at least to the first stage and second stage moving bladesfrom the upstream side among the moving blades at the plurality ofstages, and collecting the refrigerant after cooling without dischargingit into main gas, wherein the turbine, inside the rotor, has a branchpoint of the refrigerant supply path for the first stage moving bladesand the refrigerant supply path for the second stage moving blades and ajunction of the refrigerant collection path for the first stage movingblades and the refrigerant collection path for the second stage movingblades, and the refrigerant supply path and refrigerant collection pathfor the first stage moving blades and the refrigerant supply path andrefrigerant collection path for the second stage moving blades have aplurality of parallel flow paths for refrigerant supply and a pluralityof parallel flow paths for refrigerant collection to be connected to therespective refrigerant paths in the moving blades at each stage betweenthe branch point and the junction, and the sum of minimum sectionalareas of any parts of the plurality of parallel flow paths forrefrigerant supply for the second stage moving blades and the pluralityof parallel flow paths for refrigerant collection and the respectiverefrigerant flow paths in the second stage moving blades is smaller thanthe sum of minimum sectional areas of any parts of the plurality ofparallel flow paths for refrigerant supply for the first stage movingblades and the plurality of parallel flow paths for refrigerantcollection and the respective refrigerant flow paths in the first stagemoving blades.

Thereby, for the first stage moving blades and second stage movingblades which are greatly different in the necessary refrigerant flowrate, a refrigerant can be supplied and collected respectively at anappropriate refrigerant flow rate distribution.

(2) To accomplish the above first object, the present invention providesa closed circuit blade cooling turbine having the refrigerant supplyflow path and refrigerant collection path for the first stage movingblades, the refrigerant supply flow path and refrigerant collection pathfor the second stage moving blades, and a plurality of parallel flowpaths for refrigerant supply and a plurality of parallel flow paths forrefrigerant collection between the branch point and the junction,wherein at any part of the plurality of parallel flow paths forrefrigerant supply for the first stage moving blades, the plurality ofparallel flow paths for refrigerant collection, and the respectiverefrigerant flow paths in the first stage moving blades, the first metalfittings having an internal flow path are arranged, and at any part ofthe plurality of parallel flow paths for refrigerant supply for thesecond stage moving blades, the plurality of parallel flow paths forrefrigerant collection, and the respective refrigerant flow paths in thesecond stage moving blades, the second metal fittings having an internalflow path are arranged, and the sum of sectional areas of the internalflow paths of the second metal fittings is smaller than the sum ofsectional areas of the internal flow paths of the first metal fittings.

Thereby, for the first stage moving blades and second stage movingblades which are greatly different in the necessary refrigerant flowrate, a refrigerant can be supplied and collected respectively at anappropriate refrigerant flow rate distribution.

(3) To accomplish the above first object, the present invention providesa closed circuit blade cooling turbine having the refrigerant supplyflow path and refrigerant collection path for the first stage movingblades, the refrigerant supply flow path and refrigerant collection pathfor the second stage moving blades, and a plurality of parallel flowpaths for refrigerant supply and a plurality of parallel flow paths forrefrigerant collection between the branch point and the junction,wherein at any part of the plurality of parallel flow paths forrefrigerant supply for the second stage moving blades, the plurality ofparallel flow paths for refrigerant collection, and the respectiverefrigerant flow paths in the second stage moving blades, a means foradjusting the internal flow resistance is installed.

Also thereby, for the first stage moving blades and second stage movingblades which are greatly different in the necessary refrigerant flowrate, a refrigerant can be supplied and collected respectively at anappropriate refrigerant flow rate distribution.

(4) Furthermore, to accomplish the above first object, the presentinvention provides a closed circuit blade cooling turbine having therefrigerant supply flow path and refrigerant collection path for thefirst stage moving blades, the refrigerant supply flow path andrefrigerant collection path for the second stage moving blades, and aplurality of parallel flow paths for refrigerant supply and a pluralityof parallel flow paths for refrigerant collection between the branchpoint and the junction, wherein at any part of the plurality of parallelflow paths for refrigerant supply for the second stage moving blades,the plurality of parallel flow paths for refrigerant collection, and therespective refrigerant flow paths in the second stage moving blades, thethird metal fittings having an internal flow path are arranged and thethird metal fittings have a means for adjusting the internal flowresistance.

Also thereby, for the first stage moving blades and second stage movingblades which are greatly different in the necessary refrigerant flowrate, a refrigerant can be supplied and collected respectively at anappropriate refrigerant flow rate distribution.

(5) To accomplish the above first and second objects, the presentinvention provides a closed circuit blade cooling turbine having therefrigerant supply flow path and refrigerant collection path for thefirst stage moving blades, the refrigerant supply flow path andrefrigerant collection path for the second stage moving blades, and aplurality of parallel flow paths for refrigerant supply and a pluralityof parallel flow paths for refrigerant collection between the branchpoint and the junction, wherein the sum of minimum sectional areas ofany parts in the neighborhood of the connections of the plurality ofparallel flow paths for refrigerant supply for the second stage movingblades and the respective refrigerant flow paths in the second stagemoving blades and in the neighborhood of the connections of theplurality of parallel flow paths for refrigerant collection for thesecond stage moving blades and the respective refrigerant flow paths inthe second stage moving blades is smaller than the sum of minimumsectional areas of any parts in he neighborhood of the connections ofthe plurality of parallel flow paths for refrigerant supply for thefirst stage moving blades and the respective refrigerant flow paths inthe first stage moving blades and in the neighborhood of the connectionsof the plurality of parallel flow paths for refrigerant collection forthe first stage moving blades and the respective refrigerant flow pathsin the first stage moving blades.

Thereby, for the first stage moving blades and second stage movingblades which are greatly different in the necessary refrigerant flowrate, a refrigerant can be supplied and collected respectively at anappropriate refrigerant flow rate distribution and the refrigerant flowrate to the moving blades at each stage can be adjusted simply withoutbreaking down the rotor.

(6) To accomplish the above first and second objects, the presentinvention provides a closed circuit blade cooling turbine having therefrigerant supply flow path and refrigerant collection path for thefirst stage moving blades, the refrigerant supply flow path andrefrigerant collection path for the second stage moving blades, and aplurality of parallel flow paths for refrigerant supply and a pluralityof parallel flow paths for refrigerant collection between the branchpoint and the junction, wherein at any parts in the neighborhood of theconnections of the plurality of parallel flow paths for refrigerantsupply for the first stage moving blades and the respective refrigerantflow paths in the first stage moving blades and in the neighborhood ofthe connections of the plurality of parallel flow paths for refrigerantcollection for the first stage moving blades and the respectiverefrigerant flow paths in the first stage moving blades, the first metalfittings having an internal flow path are arranged, and at any parts inthe neighborhood of the connections of the plurality of parallel flowpaths for refrigerant supply for the second stage moving blades and therespective refrigerant flow paths in the second stage moving blades andin the neighborhood of the connections of the plurality of parallel flowpaths for refrigerant collection for the second stage moving blades andthe respective refrigerant flow paths in the second stage moving blades,the second metal fittings having an internal flow path are arranged, andthe sum of sectional areas of the internal flow paths of the secondmetal fittings is smaller than the sum of sectional areas of theinternal flow paths of the first metal fittings.

Also thereby, for the first stage moving blades and second stage movingblades which are greatly different in the necessary refrigerant flowrate, a refrigerant can be supplied and collected respectively at anappropriate refrigerant flow rate distribution and the refrigerant flowrate to the moving blades at each stage can be adjusted simply withoutbreaking down the rotor.

(7) Furthermore, to accomplish the above first and second objects, thepresent invention provides a closed circuit blade cooling turbine havingthe refrigerant supply flow path and refrigerant collection path for thefirst stage moving blades, the refrigerant supply flow path andrefrigerant collection path for the second stage moving blades, and aplurality of parallel flow paths for refrigerant supply and a pluralityof parallel flow paths for refrigerant collection between the branchpoint and the junction, wherein at any part in the neighborhood of theconnections of the plurality of parallel flow paths for refrigerantsupply for the second stage moving blades and the respective refrigerantflow paths in the second stage moving blades and in the neighborhood ofthe connections of the plurality of parallel flow paths for refrigerantcollection for the second stage moving blades and the respectiverefrigerant flow paths in the second stage moving blades, a means foradjusting the internal flow resistance is installed.

Also thereby, for the first stage moving blades and second stage movingblades which are greatly different in the necessary refrigerant flowrate, a refrigerant can be supplied and collected respectively at anappropriate refrigerant flow rate distribution and the refrigerant flowrate to the moving blades at each stage can be adjusted simply withoutbreaking down the rotor.

(8) To accomplish the above first and second objects, the presentinvention provides a closed circuit blade cooling turbine having therefrigerant supply flow path and refrigerant collection path for thefirst stage moving blades, the refrigerant supply flow path andrefrigerant collection path for the second stage moving blades, and aplurality of parallel flow paths for refrigerant supply and a pluralityof parallel flow paths for refrigerant collection between the branchpoint and the junction, wherein at any part in the neighborhood of theconnections of the plurality of parallel flow paths for refrigerantsupply for the second stage moving blades and the respective refrigerantflow paths in the second stage moving blades and in the neighborhood ofthe connections of the plurality of parallel flow paths for refrigerantcollection for the second stage moving blades and the respectiverefrigerant flow paths in the second stage moving blades, the thirdmetal fittings having an internal flow path are arranged and the thirdmetal fittings have a means for adjusting the internal flow resistance.

Also thereby, for the first stage moving blades and second stage movingblades which are greatly different in the necessary refrigerant flowrate, a refrigerant can be supplied and collected respectively at anappropriate refrigerant flow rate distribution and the refrigerant flowrate to the moving blades at each stage can be adjusted simply withoutbreaking down the rotor.

(9) In (2), (4), (6) and (8) mentioned above, the first and second metalfittings or the third metal fittings are preferably supply members orcollection members which are installed so as to prevent a refrigerantfrom leaking from the rotor and the gap between the first stage movingblades and the second stage moving blades.

Thereby, using the supply members or collection members installed so asto prevent a refrigerant from leaking, the refrigerant flow rate can beadjusted.

(10) In (1) to (8) mentioned above, furthermore, in the refrigerant flowpath at least on one of the still side which is a supply source of theaforementioned refrigerant and the still side which is a collectiondestination of the aforementioned refrigerant, a means for adjusting theflow resistance is installed.

By doing this, a large adjustment margin of the refrigerant flow rate ofnot only the second stage moving blades but also the first stage movingblades can be obtained.

(11) To accomplish the above first object, the present inventionprovides a closed circuit blade cooling turbine having, inside therotor, a branch point of the refrigerant supply path for the first stagemoving blades and the refrigerant supply path for the second stagemoving blades and a junction of the refrigerant collection path for thefirst stage moving blades and the refrigerant collection path for thesecond stage moving blades, wherein so that the pressure loss generatedin the refrigerant flow path and refrigerant collection flow path forthe second stage moving blades can be made larger than the pressure lossgenerated in the refrigerant flow path and refrigerant collection flowpath for the first stage moving blades, the respective flow paths areformed.

Also by doing this, for the first stage moving blades and second stagemoving blades which are greatly different in the necessary refrigerantflow rate, a refrigerant can be supplied and collected respectively atan appropriate refrigerant flow rate distribution.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing a half of the section in the direction of theturbine shaft showing the supply path of cooling air to the first stagemoving blades;

FIG. 2 is a view showing a half of the section in the direction of theturbine shaft showing the supply path of cooling air to the second stagemoving blades;

FIG. 3 is a view showing the junction surface of the fourth stage wheelfacing a stub shaft;

FIG. 4 is a view showing a half of the section in the direction of theturbine shaft showing the collection path of cooling air from the firststage moving blades and the second stage moving blades;

FIG. 5 is an enlarged view of the inlet part and outlet part of coolingair in the second stage moving blades;

FIG. 6 is an enlarged view of the inlet part of cooling air in thesecond stage moving blades;

FIG. 7 is an enlarged view of the outlet part of cooling air in thesecond stage moving blades; and

FIG. 8 is an enlarged view when a minimum sectional member is attachedto the inlet of a supply member on the upstream side.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The embodiments of the present invention will be explained in detailhereunder with reference to the accompanying drawings.

FIG. 1 is a view showing a half of the section in the axial direction ofthe turbine showing the supply path of cooling air to the first stagemoving blades in a closed circuit blade cooling turbine of thisembodiment. In this Figure, a rotor 16 is composed of a first stagewheel 1, a second stage wheel 2, a third stage wheel 3, a fourth stagewheel 4, spacers 9, 10, and 11 which are clamped by the sides of therespective wheels, a distant piece 12 connected to the side of acompressor, and a stub shaft 13 joined to the side of the fourth stagewheel 4 and the distant piece 12, the first stage wheel 1 to the fourthstage wheel 4, the spacers 9, 10, and 11 positioned between them, andthe stub shaft 13 are strongly connected by stacking bolts 14 viathrough holes 18 formed in the joined surfaces of each wheel and eachspacer. In the outer peripheries of the wheels 1, 2, 3, and 4 at therespective stages, first stage moving blades 5, second stage movingblades 6, third stage moving blades 7, and fourth stage moving blades 8are held and the whole constitutes a turbine 15. Main gas flows in thedirection from the first stage moving blades 5 to the fourth stagemoving blades 8 (in the direction from the left to the right in theFigure).

Firstly, the cooling air supply path to the first stage moving blades 5will be explained. Cooling air 17 is supplied from the still side of thebody not shown in the drawing via the inside of a bearing part 23 of thestub shaft, that is, a center hole 24 of the stub shaft and led into acavity 25 formed by the stub shaft 13 and the fourth stage wheel 4. Thecooling air 17 led into the cavity 25, via a slit 27 provided in ajunction surface 26 of the fourth stage wheel 4 and the stub shaft 13 inthe radial direction, reaches a supply hole 28 passing through thefourth stage wheel 4 in the shaft direction from the junction surface26, a supply hole 29 passing through the spacer 11, a supply hole 30passing through the third stage wheel 3, and a supply hole 31 passingthrough the spacer 10. The cooling air 17 passing through the supplyhole 31 is supplied to a supply hole 32 passing through the second stagewheel 2. The cooling air 17 passing through the supply hole 32 passingthrough the second stage wheel 2 is supplied to a slit 40 provided in ajunction surface 39 of the first stage wheel 1 and the distant piece 12in the radial direction via a supply hole 37 passing through the spacer9 and a supply hole 38 passing through the first stage wheel 1. Thecooling air 17 supplied to the slit 40 reaches a cavity 41 located inthe circular flow path on the same shaft as that of the rotor which isformed by the first stage wheel 1 and the distant piece 12 and joinsonce and then is supplied to the respective first stage moving blades 5via a hole 42 in the radial direction provided on the outer peripheryside of the first stage wheel as a parallel flow path for refrigerantsupply to the respective first stage moving blades 5.

Next, FIG. 2 is a view showing a half of the section in the direction ofthe turbine shaft showing the supply path of cooling air to the secondstage moving blades and the cooling air supply path to the second stagemoving blades 6 will be explained hereunder by referring to the drawing.The cooling air 17, in the same way as with the case of the first stagemoving blades 5, is supplied from the still side of the body not shownin the drawing via the inside of the bearing part 23 of the stub shaft13, that is, the center hole 24 of the stub shaft and led into thecavity 25 formed by the stub shaft 13 and the fourth stage wheel 4. Thecooling air 17 led into the cavity 25, via a slit 51 provided in thejunction surface 26 of the fourth stage wheel 4 and the stub shaft 13 inthe radial direction, reaches a supply hole 52 passing through thefourth stage wheel 4 in the shaft direction from the junction surface26, a supply hole 53 passing through the spacer 11, a supply hole 54passing through the third stage wheel 3, and a supply hole 55 passingthrough the spacer 10. The cooling air 17 passing through the supplyhole 55 is supplied to a slit 56 provided in a junction surface 60 ofthe second stage wheel 2 and the spacer 10. The cooling air 17 suppliedto the slit 56 reaches a cavity 57 located in the circular flow path onthe same shaft as that of the rotor which is formed by the second stagewheel 2 and the spacer 10 and joins once and then is supplied to therespective second stage moving blades 6 via a hole 58 in the radialdirection provided on the outer periphery side of the second stage wheelas a parallel flow path for refrigerant supply to the respective secondstage moving blades 6.

The junction surface 26 of the fourth stage wheel 4 facing the stubshaft 13 is shown in FIG. 3. In the outer periphery, there are boltholes 66 into which stacking bolts are inserted at twelve even intervalsin the peripheral direction. On the inner periphery side thereof, thereare slits 27 and supply holes 28 arranged at three even intervals in theperipheral direction through which cooling air for the first stagemoving blades passes and furthermore, at the same radial position, thereare slits 51 and supply holes 52 arranged at three even intervals in theperipheral direction through which cooling air for the second stagemoving blades passes. According to this embodiment, the cooling air 17supplied to the rotor 16 is branched from the cavity 25 in the rotor 16to cooling air for the first stage moving blades passing through theslits 27 and cooling air for the second stage moving blades passingthrough the slits 51 and in other words, the branch point of the twocooling air flow paths in the rotor 16 is the cavity 25.

Next, FIG. 4 is a view showing a half of the section in the axialdirection of the turbine showing the collection paths of the cooling air17 from the first stage moving blades 5 and the second stage movingblades 6 and the collection paths of the cooling air 17 from the movingblades 5 and 6 at the respective stages will be explained by referringto the drawing. The cooling air 17 collected from the respective firststage moving blades 5 reaches a cavity 72 located in the circular flowpath on the same shaft as that of the rotor which is formed by thespacer 9 and the second stage wheel 2 via a collection hole 75 installedin the outer periphery of the spacer 9 as a parallel flow path forrefrigerant collection. The cooling air 17 flowing into the cavity 72 isintroduced into a collection hole 74 formed in the spacer 9 via a slit73.

On the other hand, the cooling air 17 collected from the respectivesecond stage moving blades 6 reaches a cavity 76 located in the circularflow path on the same shaft as that of the rotor which is formed by thespacer 9 and the first stage wheel 1 via a collection hole 71 installedin the outer periphery of the spacer 9 as a parallel flow path forrefrigerant collection. The cooling air 17 flowing into the cavity 76joins collection air of the first stage moving blades 5 passing throughthe collection hole 74 via a slit 77. In other words, the junction ofthe two cooling air flow paths 17 in the rotor 16 is the outlet of thecollection hole 74. The cooling air after joining is exhausted outsidethe rotor 16 via a collection hole 78 formed in the first stage wheel 1and a collection hole 79 formed in the distant piece 12 and collectedvia the collection path on the still side of the body which is not shownin the drawing.

FIG. 5 is an enlarged view of the inlet part and outlet part of thecooling air 17 in the second stage moving blades 6. The hole 58 in theradial direction formed on the outer periphery side of the second stagewheel 2 is led to a cooling air supply hole 83 to the second stagemoving blades 6. The boundary of the hole 58 in the radial direction andthe cooling air supply hole 83 is a junction 85 at the connection wherethe second stage wheel 2 and the second stage moving blades 6 are justin contact with each other and there is a slight gap in the junction 85.To prevent the cooling air 17 from leaking from the junction 85, thehole 58 in the radial direction and the cooling air supply hole 83 areinterconnected and a supply member 81 at the metal fittings covering thejunction 85 is fit into them. The construction of each parallel flowcooling air path for the first stage moving blades is similar to thecooling air flow path 58, 81, 83 for the second stage moving blades.

The cooling air 17 after cooling the second stage a moving blades 6 isintroduced into the collection hole 71 formed in the outer periphery ofthe spacer 9 via a cooling air collection hole 84. The boundary of thecooling air collection hole 84 and the collection hole 71 is a boundary86 at the connection where the second stage moving blades 6 and thespacer 9 are just in contact with each other and there is a slight gapalso in the boundary 86. To prevent the cooling air 17 from leaking fromthe boundary 86, the cooling air collection hole 84 and the collectionhole 71 are interconnected and a collection member 82 at the metalfittings covering the boundary 86 is fit into them. The inlet part andoutlet part of the cooling air 17 in the first stage moving blades 5also have a supply member and a collection member having the sameconstitution.

Meanwhile, since main gas passing through the second stage moving bladesdoes its work in the first stage moving blades, the temperature of maingas in the second stage moving blades 6 is lower than that of the firststage moving blades 5. When the air temperature at the outlet of thecombustor is on the level of 1500° C., the difference in the temperatureof main gas between the first stage moving blades 5 and the second stagemoving blades 6 is more than 200° C. Even if the allowable metaltemperature of the first stage moving blades 5 is made higher than thatof the second stage moving blades 6 depending on the materialcharacteristics such as the material kind, single crystal, polycrystal,and others, it is impossible to compensate for more than 200° C. ofdifference in the temperature of main gas by the material and thenecessary cooling air amount of the first stage moving blades 1 is morethan that of the second stage moving blades 6.

When a constitution that the cooling air 17 can be positively suppliedmuch to the first stage moving blades 5 is used, for example, when thepath on the side of the first stage moving blades 5 is formed justwidely, the flow path resistance inside the first stage moving blades 5becomes only large (that is, the cooling air is blocked) and inverselythe pressure loss of the cooling air 17 becomes larger than that of thesecond stage moving blades 6.

As shown in FIG. 2, the pressure loss of the cooling air 17 passingthrough each flow path from the cavity 25 which is the branch point tothe collection hole 74 which is the junction is equal to each otherbetween the side of the first stage moving blades 5 and the side of thesecond stage moving blades 6, so that when the pressure loss generatedon the path on the side of the second stage moving blades 6 other thanthe inside of the second stage moving blades 6 is adjusted so as to belarger than that on the path on the side of the first stage movingblades 5 in correspondence to that the pressure loss of cooling airinside the first stage moving blades 5 is larger, the cooling air 17 canpass much through the first stage moving blades 5 smoothly.

To increase the pressure loss generated on the path on the side of thesecond stage moving blades 6, the length of the path on the side of thesecond stage moving blades 6 is made longer than the length of the pathon the side of the first stage moving blades 5 or the sum of minimumsectional areas of a plurality of paths installed on the side of thesecond stage moving blades 6 is made smaller than the sum of minimumsectional areas of a plurality of paths installed on the side of thefirst stage moving blades 5. From the viewpoint of the structure, aconstitution of adjusting the sectional area can be easier manufacturedthan a constitution of changing the path length.

FIG. 6 is an enlarged view of the inlet part of the cooling air 17 inthe second stage moving blades 6 shown in FIG. 5. To make the sum ofminimum sectional areas of the respective paths on the side of thesecond stage moving blades 6 smaller than the sum of minimum sectionalareas of the respective paths on the side of the first stage movingblades 5, a minimum sectional member 91 is incorporated in the supplymember 81. FIG. 7 is an enlarged view of the outlet part of the coolingair 17 in the second stage moving blades 6 shown in FIG. 5. To make thesum of minimum sectional areas of the respective paths on the side ofthe second stage moving blades 6 smaller than the sum of minimumsectional areas of the respective paths on the side of the first stagemoving blades 5, a minimum sectional member 92 is incorporated in thecollection member 82. These minimum sectional members 91 and 92 functionas limiting plates (or orifice plates) for flowing of the cooling air 17and according to this embodiment, a configuration that they areincorporated in both of the supply member 81 and the collection member82 is used. However, even when the minimum member is installed in eitherof them, it functions sufficiently.

A general turbine has a structure that the moving blades of the turbinecan be mounted, demounted, or exchanged without removing the stackingbolts 14 and breaking down the rotor 16. Therefore, the supply member 81and the collection member 82 are structured so as to be taken out easilyby removing the moving blades and the supply member 81 and thecollection member 82 can be also mounted, demounted, or exchangedwithout removing the stacking bolts 14 and breaking down the rotor 16.

Even if the sectional area and resistance of the cooling air supply flowpath in the rotor 16, the flow path resistance inside the cooling movingblades, and the sectional area and resistance of the cooling aircollection flow path in the rotor are estimated at the design stage andeach flow path is designed and manufactured on the basis of it so thatan appropriate flow rate flows in the moving blades at each stage, whenthe gas turbine is actually operated, the metal temperature of each ofthe first stage moving blades 5 and the second stage moving blades 6 iseasily varied and apt to be deviated from the design value, so that theaccuracy is limited and it is necessary to adjust the cooling air amountaccording to the metal temperature of each of the first stage movingblades 5 and the second stage moving blades 6 after assembly andmanufacture. When the minimum sectional member 91 is incorporated in thesupply member 81 or the minimum sectional member 92 is incorporated inthe collection member 82 and the cooling air amount is adjusted bychanging the flow path area of the minimum sectional member, withoutremoving the stacking bolts 14 and breaking down and reassembling therotor 16 requiring troublesome adjustment, the flow rate can be simplyadjusted, and the operation time can be shortened greatly, and the costcan be reduced.

When the supply member 81 and the collection member 82 themselves are tobe exchanged, or the minimum sectional members 91 and 92 are to beexchanged, or the flow rate is to be adjusted by grinding the flow pathsof the minimum sectional members 91 and 92, the supply member 81 and thecollection member 82 are excellent in operability because they are smallas parts.

Furthermore, by attaching the minimum sectional member 91 to the supplymember 81 instead of attaching the minimum sectional member 92 to thecollection member 82, the pressure loss is generated by the minimumsectional member 91 before passing through the blades, so that thecooling air pressure in the second stage moving blades 6 lowers. Thecooling air leakage amount from cracks and gaps generated in the secondstage moving blades 6 becomes smaller in correspondence to the lowercooling air pressure.

As shown in FIG. 8, when a minimum sectional member 93 is attached tothe inlet on the upstream side of the supply member 81, the leakage tothe junction 85 can be suppressed more.

When the number of supply holes 52 for the second stage moving bladesshown in FIG. 3 is made smaller than the number of supply holes 28 forthe first stage moving blades and the diameter of the supply holes 52 ismade smaller than the diameter of the supply holes 28, the sum ofminimum sectional areas of the respective cooling air paths on the sideof the second stage moving blades can be also made smaller than the sumof minimum sectional areas of the respective cooling air paths on theside of the first stage moving blades.

Even if the supply member 81 and the collection member 82 are notprovided, only the minimum sectional member 91 and the minimum sectionalmember 92 can be attached and for example, there is a constitutionavailable that a deep facing hole is formed on the same axis as that ofthe refrigerant flow path from the junction 85 or the boundary 86 and aminimum sectional member having the same outer diameter as that of thehole is fit in. When a constitution that when the moving blades areremoved, the minimum sectional member can be easily mounted or demountedis used like this, even if the minimum sectional member is positionedaway from the neighborhood of the junction 85 and the boundary 86, theflow rate can be simply adjusted without breaking down the rotor 16.

Furthermore, on the side of the stub shaft 13 shown in FIG. 2, forexample, a flow path adjustment mechanism of the cooling air path on theside of the second stage moving blades such as screw type parts foradjusting the flow path by changing the flow path area by changing thescrew depth can be attached.

When the flow rate is to be adjusted only by the cooling air path sideon the side of the second stage moving blades inside the rotor 16, thecooling air flow rate of the second stage moving blades 6 can beadjusted greatly by the function of the aforementioned adjustmentmechanism, that is, the adjustable range (hereinafter referred to as anadjustment margin) is large. However, the adjustment margin of thecooling air flow rate of the first stage moving blades 5 is smaller thanthat of the second stage moving blades 6 because there is no mechanismfor directly adjusting it. If a constitution that not only the flow rateadjustment only by the cooling air path on the side of the second stagemoving blades but also the flow rate adjustment can be performed also onthe still side of the body before introduced into the rotor 16 beforecooling air for the first stage moving blades and cooling air for thesecond stage moving blades branch is used, the adjustment margin of thecooling air flow rate of the first stage moving blades 5 also can betaken large. Namely, the flow rate of the first stage moving blades isadjusted in flow rate adjustment on the still side of the body and theflow rate of the second stage moving blades is adjusted in flow rateadjustment of the cooling air path on the side of the second stagemoving blades in the rotor 16. The constitution of the still side of thebody not shown in the drawing is a constitution that a supply pipe ofthe cooling air 17 and a collection pipe of cooling air are provided.

This embodiment uses a constitution that the supply branch point forsupplying a refrigerant to the first stage moving blades and the secondstage moving blades and the collection junction of a refrigerant to becollected from the first stage moving blades and the second stage movingblades are provided inside the rotor. However, the application of thepresent invention is not limited to such a constitution. As long as aconstitution that as mentioned above, by making the sum of minimumsectional areas of a plurality of paths installed in parallel with eachother for each flow path to be connected to each moving blade stagedifferent for each flow path for each moving blade stage, therefrigerant flow rate distribution is adjusted is used, even if thepresent invention is applied to a constitution that for example, atleast one of the supply branch point and collection junction isinstalled on the still side of the body and the supply flow inlet orcollection exhaust outlet corresponding to each moving blade stage isinstalled in the rotor and connected to each moving blade stage, theeffects of the present invention can be obtained.

The present invention can be applied also to a case that the movingblades of the third and subsequent stages are to be cooled in the futureand in this case, so that the sum of minimum sectional areas of therespective paths on the moving blade stage side relatively positioned onthe downstream side in the flow direction of main gas is made smallerthan the sum of minimum sectional areas of the respective paths on themoving blade stage side relatively positioned on the downstream side, itis desirable to adjust the sectional area of flow path of the minimumsectional member to be incorporated in each supply member.

The aforementioned embodiment is explained on the assumption that thepresent invention is applied to a gas turbine having an object of usingcompressed air as a refrigerant and taking out rotational axis force.However, the present invention is not limited to it. For example, thepresent invention can be applied to a gas turbine having a constitutionthat an exhaust heat collection boiler is installed in the gas turbineand vapor generated by it is used for a refrigerant, a constitution thatnitrogen gas generated as a by-product when the gas turbine is used tosupply power of a chemical refining plant is used as a refrigerant, or aconstitution that exhaust gas is used for jet thrust.

As explained above, according to the present invention, for the firststage moving blades and second stage moving blades which are greatlydifferent in the necessary refrigerant flow rate, a refrigerant can besupplied and collected at an appropriate refrigerant flow ratedistribution respectively.

According to the present invention, the refrigerant flow rate to eachstage moving blades can be adjusted simply without breaking down therotor.

Furthermore, according to the present invention, using a supply memberor a collection member to be installed so as to suppress leakage of arefrigerant, the refrigerant flow rate can be adjusted.

According to the present invention, the adjustment margin of therefrigerant flow rate of not only the second stage moving blades butalso the first stage moving blades can be increased.

What is claimed is:
 1. A closed circuit blade cooled turbine havingmoving blades at a plurality of stages arranged in a flowing directionof a main gas of a gas turbine and fixed to the outer periphery of arotor, supplying a refrigerant at least to the first stage and secondstage moving blades from an upstream side among said moving blades atsaid plurality of stages, and collecting said refrigerant after coolingwithout discharging it into the main gas, wherein said turbine, insidesaid rotor, has a branch point of a refrigerant supply path for saidfirst stage moving blades and a refrigerant supply path for said secondstage moving blades and a junction of a refrigerant collection path forsaid first stage moving blades and a refrigerant collection path forsaid second stage moving blades, said refrigerant supply path and saidrefrigerant collection path for said first stage moving blades and saidrefrigerant supply path and said refrigerant collection path for saidsecond stage moving blades have a plurality of parallel flow paths forrefrigerant supply and a plurality of parallel flow paths forrefrigerant collection to be connected to said respective refrigerantpaths in said moving blades at each said stage between said branch pointand said junction, first metal fittings having an internal flow path arearranged at any part of said plurality of parallel flow paths forrefrigerant supply for said first stage moving blades, said plurality ofparallel flow paths for refrigerant collection, and said respectiverefrigerant flow paths in said first stage moving blades, second metalfittings having an internal flow path are arranged at any part of saidplurality of parallel flow paths for refrigerant supply for said secondstage moving blades, said plurality of parallel flow paths forrefrigerant collection, and said respective refrigerant flow paths insaid second stage moving blades, and the sum of sectional areas of saidinternal flow paths of said second metal fittings is smaller than thesum of sectional areas of said internal flow paths of said first metalfittings.
 2. A closed circuit blade cooled turbine according to claim 1wherein third metal fittings having an internal flow path are arrangedat any part of said plurality of parallel flow paths for refrigerantsupply for said second stage moving blades, said plurality of parallelflow paths for refrigerant collection, and said respective refrigerantflow paths in said second stage moving blades, said third metal fittingshaving means for changing an internal flow resistance.
 3. A closedcircuit blade cooled turbine according to claim 1 wherein at any partsin the neighborhood of connections of said plurality of parallel flowpaths for refrigerant supply for said second stage moving blades andsaid respective refrigerant flow paths in said second stage movingblades and in the neighborhood of connections of said plurality ofparallel flow paths for refrigerant collection for said second stagemoving blades and said respective refrigerant flow paths in said secondstage moving blades, third metal fittings having an internal flow pathare arranged, and said third metal fitting has means for changing aninternal flow resistance.
 4. A closed circuit blade cooled turbineaccording to claim 1, wherein said first and second metal fittings are asupply member or a collection member to be installed so as to suppressleakage of a refrigerant from gaps between said rotor and said firststage moving blades and said second stage moving blades.
 5. A closedcircuit blade cooled turbine having moving blades at a plurality ofstages arranged in a flowing direction of a main gas of a gas turbineand fixed to the outer periphery of a rotor, supplying a refrigerant atleast to first stage and second stage moving blades from an upstreamside among said moving blades at said plurality of stages, andcollecting said refrigerant after cooling without discharging it intothe main gas, wherein said turbine, inside said rotor, has a branchpoint of a refrigerant supply path for said first stage moving bladesand a refrigerant supply path for said second stage moving blades and ajunction of a refrigerant collection path for said first stage movingblades and a refrigerant collection path for said second stage movingblades, said refrigerant supply path and said refrigerant collectionpath for said first stage moving blades and said refrigerant supply pathand said refrigerant collection path for said second stage moving bladeshave a plurality of parallel flow paths for refrigerant supply and aplurality of parallel flow paths for refrigerant collection to beconnected to said respective refrigerant paths in said moving blades ateach said stage between said branch point and said junction, and meansfor changing an internal flow resistance is installed at any part ofsaid plurality of parallel flow paths for refrigerant supply for saidsecond stage moving blades, said plurality of parallel flow paths forrefrigerant collection, and said respective refrigerant flow paths insaid second stage moving blades, said means for changing an internalflow resistance comprising a replaceable member having a constant flowresistance.
 6. A closed circuit blade cooled turbine having movingblades at a plurality of stages arranged in a flowing direction of amain gas of a gas turbine and fixed to the outer periphery of a rotor,supplying a refrigerant at least to first stage and second stage movingblades from an upstream side among said moving blades at said pluralityof stages, and collecting said refrigerant after cooling withoutdischarging it into the main gas, wherein said turbine, inside saidrotor, has a branch point of a refrigerant supply path for said firststage moving blades and a refrigerant supply path for said second stagemoving blades and a junction of a refrigerant collection path for saidfirst stage moving blades and a refrigerant collection path for saidsecond stage moving blades, said refrigerant supply path and saidrefrigerant collection path for said first stage moving blades and saidrefrigerant supply path and said refrigerant collection path for saidsecond stage moving blades have a plurality of parallel flow paths forrefrigerant supply and a plurality of parallel flow paths forrefrigerant supply and a plurality of parallel flow paths forrefrigerant collection to be connected to said respective refrigerantpaths in said moving blades at each said stage between said branch pointand said junction, at any parts in th e neighborhood of connections ofsaid plurality of parallel flow paths for refrigerant supply for saidfirst stage moving blades and said respective refrigerant flow paths insaid first stage moving blades and in the neighborhood of connections ofsaid plurality of parallel flow paths for refrigerant collection forsaid first stage moving blades and said respective refrigerant flowpaths in said first stage moving blades, first metal fittings having aninternal flow path are arranged, at any parts in the neighborhood ofconnections of said plurality of parallel flow paths for refrigerantsupply for said second stage moving blades and said respectiverefrigerant flow paths in said second stage moving blades and in theneighborhood of connections of said plurality of parallel flow paths forrefrigerant collection for said second stage moving blades and saidrespective refrigerant flow paths in said second stage moving blades,second metal fittings having an internal flow path are arranged, and thesum of sectional areas of said internal flow paths of said second metalfittings is always smaller than the sum of sectional areas of saidinternal flow paths of said first metal fittings.
 7. A closed circuitblade cooled turbine having moving blades at a plurality of stagesarranged in a flowing direction of a main gas of a gas turbine and fixedto the outer periphery of a rotor, supplying a refrigerant at least tothe first stage and second stage moving blades from an upstream sideamong said moving blades at said plurality of stages, and collectingsaid refrigerant after cooling without discharging it into the main gas,wherein said turbine, inside said rotor, has a branch point of arefrigerant supply path for said first stage moving blades and arefrigerant supply path for said second stage moving blades and ajunction of a refrigerant collection path for said first stage movingblades and a refrigerant collection path for said second stage movingblades, said refrigerant supply path and said refrigerant collectionpath for said first stage moving blades and said refrigerant supply pathand said refrigerant collection path for said second stage moving bladeshave a plurality of parallel flow paths for refrigerant supply and aplurality of parallel flow paths for refrigerant collection to beconnected to said respective refrigerant paths in said moving blades ateach said stage between said branch point and said junction, and at anyparts in the neighborhood of connections of said plurality of parallelflow paths for refrigerant supply for said second stage moving bladesand said respective refrigerant flow paths in said second stage movingblades and in the neighborhood of connections of said plurality ofparallel flow paths for refrigerant collection for said second stagemoving blades and said respective refrigerant flow paths in said secondstage moving blades, means for changing an internal flow resistance isinstalled, said means for changing an internal flow resistancecomprising a replaceable member having a constant flow resistance.
 8. Aclosed circuit blade cooled turbine having moving blades at a pluralityof stages arranged in a flowing direction of a main gas of a gas turbineand fixed to the outer periphery of a rotor, supplying a refrigerant atleast to first stage and second stage moving blades from an upstreamside among said moving blades at said plurality of stages, andcollecting said refrigerant after cooling without discharging it intothe main gas, wherein said turbine, inside said rotor, has a branchpoint of a refrigerant supply path for said first stage moving bladesand a refrigerant supply path for said second stage moving blades and ajunction of a refrigerant collection path for said first stage movingblades and a refrigerant collection path for said second stage movingblades, and said refrigerant supply path and said refrigerant collectionpath for said first stage moving blades and said refrigerant supply pathand said refrigerant collection path for said second stage moving bladeshave a plurality of parallel flow paths for refrigerant supply and aplurality of parallel flow paths for refrigerant collection to beconnected to said respective refrigerant paths in said moving blades ateach said stage between said branch point and said junction, and the sumof minimum sectional areas of any parts of said plurality of parallelflow paths for refrigerant supply for said second stage moving bladesand said plurality of parallel flow paths for refrigerant collection andsaid respective refrigerant flow paths in said second stage movingblades is always smaller than the sum of minimum sectional areas of anyparts of said plurality of parallel flow paths for refrigerant supplyfor said first stage moving blades and said plurality of parallel flowpaths for refrigerant collection and said respective refrigerant flowpaths in said first stage moving blades, and which further includes, insaid refrigerant flow path at least on one of a still side which is asupply source of said refrigerant and a still side which is a collectiondestination of said refrigerant, means for changing a flow resistance.